F53 AC high side pressure (2008 - 134a) at 90F

Normal low side pressure is 40-45 the night side will very based on temp how clean the child is etc. if you are charging it do it based on suction pressure.

You never charge a system based on low side. IF you charge you watch the hi side with the lo side as a help. Doug

A/C System Operating Pressures for 134a systems
Ambient Air Temp (F) Entering Condenser Suction Pressure (PSIG) @ Evaporator Outlet Discharge Pressure (PSIG) @ Compressor Outlet

50-----5-15--- 75-125
60---- 5-15--- 100-150
70---- 10-20---125-175
80---- 10-20-- 150-225
90---- 15-25-- 175-250
100--- 15-25---200-275
110--- 15-30-- 225-325

Thanks,

Most website charts show 45-55 low side, and mine is at 50.

The high goes from 275 at idle to 320 when held at about 2000 rpm for a while.

An old (R-12 era) GM manual says to take the readings at 2000 rpm but I haven't seen that elsewhere.

Your coils are dirty

I hope you're talking about the condenser. That's in front of the radiator and looks pretty clean.

I hope it's not the evaporator. I pulled the drain hose off and over a cup of water came out.

Does anyone know what is used to seal the drain hole ?

Even if it looks clean it may not be. Can you see all the way through it? If the evap has a filter hopefully it is fairly clean but should still be acid washed just in case. I would take a hose and clean the condenser.

spotrot wrote:
Thanks,

Most website charts show 45-55 low side, and mine is at 50.

The high goes from 275 at idle to 320 when held at about 2000 rpm for a while.

An old (R-12 era) GM manual says to take the readings at 2000 rpm but I haven't seen that elsewhere.

My Chart is from the largest supplier of Dash AC systems for RV's--Evans Tempcon. Doug